This invention relates to high frequency switching circuits and, more particularly, to a high frequency switching circuit of voltage resonance type using a single-ended switching circuit.
As the power sources for peripheral units of a computer system and conventional communication devices, low-voltage, high-current stabilized power sources have been used. These power sources are, in many cases, switching power sources, which have the advantages of small size, light weight and high efficiency. Among these switching power sources, those which make use of voltage or current resonance waves have sufficient switching efficiency of main switching element (such as a transisitor, a thyristor, a MOSFET, etc.) and can operate with low noise. On the demerit side, however, a voltage resonance type switching circuit which is based on a single-ended switching circuit is prone to intermittent current through a filtering capacitor. This intermittent current induces noise voltage in the equivalent resistance or inductance of the filtering capacitor and also increases power loss in the filtering capacitor. Further, where high power is supplied to a load by intermittent current, the peak value of current flowing thhrough a rectifier diode amounts to several times the average current to increase power loss in the rectifier diode.